Propellent injection system with safety valve to cut off fluid pressure supply



PROPELLENT INJECTION SYSTEM WITH SAFETY VALVE TO CUT OFF FLUID PRESSURE SUPPLY Filed Dec. 27, 1949 P 1952 F B. HALFORD ETAL 2, 6l2,019

sTARTl N6 VALVE.

.F/GZ. 36 25 24 F Z\ A 1 1 34 vii S .33 j 428 1277: d F I 39 Aitomeys Patented Sept. 30, 1952 PRoPEL EN-T INJECTION SYSTEM WITH SAFE-TY VALVE T our OFF FLUID PRESSURE SUPPLY Frank Bernard Halford,'Edg'ware, Arthur Valentine -Cleave'r, London, and Ernest Baker Dave, East Barnet', England, assignors to The De Havilland Engine Company Limited, Sto'negro ve E'elg'ware, England a company of Great Britain. 1

Application-December 27, 1949, "Serial No. 135,285 In Great Britain January 3, 1949 1 This invention relates to rocket=-type prbpuh s-ion apparatus of the kind in which compressed air is employed to force propellent liquid or liquidsfrom a reservoir or reservoirs into a reaction chamber, in which a reaction takes place" accom panied by the evolution of gases which issue from a nozzle with propulsive effect.

The compressed air may, of course; be replaced by another compressed gas, but the term "com"- pressed air will be used for convenienceas embraci'ng either air or any other suitable gas.

In such rocket apparatus theco'mpressed air generally passes through a number of valves on its way toth'e' liquid reservoirs, foi'xinstance first through a reducing valve which reduces its pressure from the order'of hundreds "of atmospheres in a storage-container tofsay, t nsor atmospheres in the rest of theapparatu's, which will be termed the low pressurepart. Distributor valves may be provided in the lower pressurepart of the apparatus for distributing the compressed airt'o' the various reservoirs for propellent liquids: A starting valve may also beprovided for admitting the compressed air to the'd-istribu'tbr valves and the parts of the apparatus beyond- -them when it is desired to bring the "apparatus-into opera-'- tion. In the United; States patent specification- Serial No. 135,284, fi-led Decen-iber 2r;--1-949,'in-the=' names of thap'res'ent applicantsit is -a1soproposed to: provide'what is termed-a check' ti-irust valve before the starting valve for the p'ur'pds'e' of enabling the operator to ascertain whether the various parts of the apparatuszar'" in working condition before setting it in full o ener -n,

According to the present invention in a'rocket type propulsion appara'tus'of theikind specified, and in which a reducing valve is provided, an air release valve is provided'betwee'n the reducing valve. and other valves in the apparatus,- which can be opened to' allo'w compressed-ante pass through it to the rest of the-low pressure part of the apparatus when the rocket-is t'ofbe' opeb a-t'ed, but which is arranged: to close" automatically should the pressure in the low pressurepart or the apparatus before the a'ir release valve rise' above a predetermined value; Thus the air release valve serves asasafety 5 Claims. (crisp-35.5)

device for ensuring thattheother valves in the I low pressure part of the apparatuscannot besuba jected to an undesirably -high'air pressuresior' instance in the event of the reducing valve failing t'o-work correctly. U jj In order that it shall'work in this'jr'nanner' the air release valve may' include an c -unm ment which when the air pressure in th'e'low' dicate d Figural", it consists o'fa reaction' ch aini' V The invention 2 pressure part of the apparatus is applied to it causes the valve toclose, and a" pilot valve arranged to allow air from the low pressure part of the apparatus to act on the actuating element when the pressure in the low pressure part of the'appa'ratus before the air'release valve' exceeds a predetermined value; 'Ihepilot valve may conveni'entl'y be urged towards a seating by asp'rlng in opposition to thepressure of the airin tl'i'e' 10w pressure part of the apparatus, and means may be provided for varying'the'loading of'f'the spring. Thus when the air release valve 'isto' rem'ai'nclosed the" spring loading will bea minirnuin so that the air' pressurecan easily lift the pilot valve from its seating and act on th'eactua'ting element which holds theai'r 'r'elease'v'a'lve'. closed. A 3

' Know the air release valve isito" be opened the spring loading is increased until the pilot valve is held on its' seating'. In moving on toiits' seat' ing' the pilot valve exposesthe actuating element to the atmosphere. allowing the pressure of the air in the a paratus to open thei ai'r release valve and tokeep itfope'n for so long as'the pilot valv'e remains oniits seat; If, however, the air-pressure in" the low pressure part of the apparatus berdre,

the air release" valve should exceed a'p're'det mined value, the spring force will beinsufiici nt' tqhold the] pilot valve on its seat-st that lift and oncefrnore subj'ect"theactiiating'e to the pie reof the air in the ap'par us j'Ih'e main valv 'uitnererore close and r'e'ina" 'Telbsd' unti'l such' time as the pressure has fallen fciently' to enable the pi1ot valve to resufne it"s Thef 'cons'truction of the vaive 'ma'y 'bevaried. considerably, but jcenv'enientl the actiia'ting"e1e-- ment is constitute'd'byfthe piston of (a pneu'niatic' servo motori "1 f, f maybe'carried int'oeffec in varicus'ways, butpne particular arr ange'ment will, he described by way ofjexample'with reference: tofthe acc'on'ip'anyin'g drawing, as app-lied t rocket unit intendedfor installation inor a'tt'a v merit 1701,2111 "aircraft for assisting its take "off.

the drawing, p Figure 1 is a"{(1 ia'gram" of I the general arrange; ment of the rocketunit; and

' Figure2isa' diagrammatic cross sectiibn offbne The general. arra eme t an i -.f rmiiidfthe rocketlunit istdescribediin United States Sfieci non serial No. 1351282,filediDeceinber 27,194

thenaineso'fFrank BernardI-la anna-2n a l valentine qleaven 'Broadly speaking,an, .1

her It into which can be injected a main propellent, for instance hydrogen peroxide, from a reservoir H, and a secondary propellent, for instance sodium or calcium permanganate which acts as a dissociation catalyst for hydrogen peroxide, from a reservoir iii. The liquids are injected by compressed gas, for instance, air, which is stored in bottles 13.

The compressed air passes through an automatic reducing valve I l and then through the air release valve l5, shown in Fig. 2, which is the subject of the present invention and will be described in detail below. After leaving the air release valve the compressed air passes to a check thrust valve and thence to a starting valve l1. Then this starting valve is opened compressed air passes through it and opens a catalyst air distributor valve i 8, which allows compressed air to flow through a pipe l9 and enter the catalyst reservoir [2 and so inject the catalyst into the reaction chamber iii. A portion of the compressed air which has passed through the catalyst air distributor valve 18 flows along a pipe ,28 and opens a hydrogen peroxide air distributor valve 2|, thus allowing compressed air to flow through a pipe 22 and enter the hydrogen peroxide reservoir H and so inject hydrogen peroxide into the'reaction chamber 10 through an automatic injector valve 23. The hydrogen peroxide thereupon dissociates producing propellent gases which issue through a reaction nozzle48.

The air release valve i5, which is shown diagrammatically in Figure 2, consists of two valve members, namely a main valve member 24 which, whenit is opened, allowscompressed air to pass in the direction of the arrow 25 from the reducing valve M to an outlet passage 26, whence'it goes to the check thrust valve H6. The second valve member comprises a pilot valve 27 which controls'the movement of the main valve member 24.

The valve housing 23 is divided by transverse partitions 29 and 33 into three chambers. The upper chamber 31 communicates with the reducing valve M, while the centre chamber 32 communicates with the outlet passage 23 and thence with the check thrust valve 55. partition 29 between these chambers constitutes a seating for the main valve member 24, and when the main valve member is closed air cannot pass from the upper chamber ,3} to the centre chamber 32. The third chamber 41 constitutes a cylinder'in which can move a piston 33'connectied to the main valve member 24, the part of the chamber 4! above the piston being vented at all times to the atmosphere through a port 3 5.

A tubular element 36 extends through the centre of the two lower. chambers 32 and 41 and opens into the upper, chamber 3|. This tubular element accommodates the pilot valve 21. The main valve member 24 and the piston 34 can slide freely upon the tubular element 36, but a fluid seal 31 isprovided to prevent leakage of air along the sliding surfaces. The pilot valve 21 consists of a double-ended needle valve which can move between two seats 38 and 39 formed inv transverse partitions in the tubular element 36, so as to close one or the other. in the upper seatv 38 is preferably slightly smaller thanthat in the lower seat 39. The space between these seatscontaining the. pilot valve 21 communicates through a port iii'with a sealed chamber 41 below the piston 34., The interior of the tubular element 36 above the upper seat The.

The aperture 38 communicates with the chamber 3|, while the interior of the tubular element 36 below the lower seat 39 communicates with the atmosphere. The latter part of the tubular element also contains a compression spring 41 which bears against the pilot valve 21 through a stem 42, and tends to hold it against its upper seat 38.

At the lower end of the spring 4| there is a movable abutment 43 which can be raised or lowered by means of a cam 44 under the control of the air craft pilot for varying the loading of the spring.

The chamber 41 is sealed by a fluid seal 45 of the bellows type. One end of this seal engages the periphery of the piston 34 while the other end engages the periphery of a flange 46 which extends from the tubular element 36.

When the spring 4| is heavily loaded, the pilot valve 21' generally occupies its upper position engaging the seat 38 so that the chamber 33 beneath the piston 34 will be maintained in communication with the atmosphere through the seat 39 and the port 40. The pressure of the compressed air on the main valve member 2 3 thus moves it from its seating in the partition 29, so that compressed air can flow Without hindrance from the reducing valve [4 to the check thrust valve 16. On the other hand when the loading of the spring 4! is eased until the pilot valve 27 assumes its lower position on the seat 39, compressed air enters the chamber 33 beneath the piston 34 through the seat 38 and the port 48. and so raises the piston 34 and forces the main valve member 24 on to its seat, thus cutting off the supply of compressed air to the check thrust valve, and to the rest of the low pressure part of the rocket unit.

If, however, the spring 4! is heavily loaded so that the main valve member 24 should be open, but the pressure of the compressed air is excessive, this pressure will nevertheless force the pilot valve 21 from its upper seat 38 against the action of the spring 4!. The pilot valve will thus admit compressed air to the chamber 33 below the piston 34 and hold the main valve member 24 firmly on to its seating. Thus should there ever be an excessive pressure beyond the reducing valve M, for instance in the event of a failure of that valve, the air release valve i5 will prevent this excessive pressure from reaching the rest of the low pressure part of the rocket unit.

What we claim as our invention and desire to secure by. Letters Patent is:

1; Rocket propulsion apparatus consisting of a high pressure part comprising at least one storage container for gaseous pressure medium and a pressure-reducing valve adapted to reduce the pressure of the gaseous medium issuing from said storage container, and a low pressure part consisting of the part beyond said pressure-reducing valve and comprising at least one reservoir for propellent liquid, a reaction chamber, a propulsion nozzle extending rearwardly from said reaction chamber, control means for admitting gaseous pressure medium to said reservoir to pressurize said reservoir and inject propelient liquid into the reaction chamber for gas-produc ing reaction therein, and a release valve situated between said pressure-reducing valve and the rest of the low pressure part of the apparatus, said release valve comprising a closure member, actuating means for said closure member, and a pressure-responsive element communicatingwith the low pressure part of the apparatus upstream of said closure member and controlling said actuating means, whereby said closure member is fully open when the pressure acting on said pressure-responsive element is below a predetermined value and is fully closed when said pressure is above said predetermined value.

2. Rocket propulsion apparatus as claimed in claim 1, which also includes overriding control means for said release valve whereby the closure member thereof can be closed irrespective of the pressure in the low pressure part of the apparatus.

3. Rocket propulsion apparatus, as claimed in claim 1, in which the actuating means for the closure member of the release valve is pressure actuated and is arranged to close said closure member when pressure is applied thereto and said pressure responsive element comprises a pilot valve which is moved to admit pressure medium to said actuating means when the pressure in the low pressure part of the apparatus exceeds said predetermined value.

4. Rocket propulsion apparatus, as claimed in claim 3, in which the actuating'means for the closure member of the release valve comprisesa piston of a piston and cylinder type pneumatic servomotor, said pilot valve constitutes the control valve of said servomotor and the gaseous pressure medium in the low pressure part of the apparatus constitutes the pneumatic working medium of said servomotor.

5. Rocket propulsion apparatus as claimed in claim 3, which includes a seating for said pilot valve, a spring adapted to urge said pilot valve on to said seating in opposition to the pressure of the gaseous pressure medium in the low pres-' sure part of the apparatus before the release valve, and an adjustable abutment for said spring.

FRANK BERNARD I-IALFORD. ARTHUR VALENTINE CLE AVER. ERNEST BAKER DOVE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Journal of the American Rocket Society, No. 72, Dec. 1947, pages 47 and 48. 

